RE: RDF from RDBMS

> I'd be very grateful if anyone can point me towards info/links
concerning
> the extraction of RDF (or other metadata) from existing databases.

http://www-db.stanford.edu/~melnik/rdf/db.html

(If you are instead looking for information about extracting metadata
about the databases themselves and things like data lineage, then check
out http://www.omg.org/technology/cwm/, which describes the metadata
model that most all DBMS vendors have agreed on.  The link at
http://www.mdcinfo.com/ describes the OIM that was implemented in
Microsoft [http://www.microsoft.com/sql/techinfo/mds.htm] , Sybase,
Cognos, Hyperion, etc. and will now be merged into the OMG effort).